It turns out that Vines are actually six and a half seconds long, not six.
James Martin/CNET

Among the many curiosities about Twitter's Vine app has been how the company decided six seconds was the magic number for a clip's length.

Well, guess what? It turns out that the maximum length of a Vine isn't six seconds at all. In fact, they top out at six and a half seconds.

And how do we know? After watching a Vine today that was tweeted by Twitter co-founder Jack Dorsey, I came away with the feeling that it felt longer than advertised. A bit of quick work by CNET videographer Jared Kohler, using iShowU, then proved that a Vine works out to six seconds and 14 frames, played at 28.77 frames per second. In other words, just under six and a half seconds. Don't believe it? Check out the Vine below.

What does that mean? Well, it means you're actually getting 8.3 percent more video than you thought you were. And that's a good thing, right?

But the fact that the videos are really six and a half seconds long does make one wonder why that's the length. At the time of Vine's launch last month, Twitter explained that the six-second limit was a choice made after lots of testing. "The team tested various video lengths, ranging from about four seconds to ten seconds, as they were building Vine," a Twitter representative told CNET at the time. "They found that six seconds was the ideal length, from both the production and consumption side."

Aha! But then why is the real number six and a half seconds? Is that extra half-second crucial for production and/or consumption? It's hard to say because Twitter didn't respond to a new request for comment. And because, let's be honest, an extra half a second isn't all that big a deal.

Still, if the folks at Vine were making an arbitrary decision about length, then why did they actually settle on six and a half seconds instead of six? We'd love your thoughts -- even those that make fun of us for caring about small details like this. Please leave them in the comments section, if you've got half a second.